What is recurrent abdominal pain?

The most formal definition of recurrent abdominal pain, published almost 50 years ago, states that children have recurrent abdominal pain when there are at least three bouts of abdominal pain, which are severe enough to affect activities, over a period of three months. In reality, children are diagnosed with recurrent or chronic abdominal pain after a period of one or two months.

The pain may occur on a daily basis, or it may be intermittent. The pain may occur at any part of the abdomen, but, as a general rule, it is classified as upper abdominal (between the bottom of the breast bone and the belly button), around the belly button, or in the lower abdomen.

What causes abdominal pain?

Recurrent abdominal pain in children generally is categorized in one of three groups. The first group includes an obvious disease, i.e., there is a structural, biochemical, or other abnormality that is shown by examination or testing. Examples include, among others, peptic ulcer disease, inflammatory bowel disease, infections, gynecologic pathology, and kidney disease. As a group, these conditions generally are found in about 10% to 20% of children with recurrent abdominal pain. The second group includes "functional gastrointestinal disorders."

These disorders have a fairly standard set of symptoms, and, despite evaluation, no organic disease can be found. The two most common conditions are irritable bowel syndrome and functional dyspepsia. Children in the third group also have functional abdominal pain (no obvious disease can be found). However, their symptoms are not as readily describable as the symptoms associated with irritable bowel syndrome or functional dyspepsia. In children in the third group, "somatization" is often more prominent. Somatization is the process of experiencing and communicating physical distress and symptoms, which are not explained by physical findings, and excessively seeking medical care for the complaints.

Who gets recurrent abdominal pain?

Studies have shown that abdominal pain is a very common problem. Up to 75% of middle school and high school students have abdominal pain over the course of the year, with almost 1 in 5 having the pain on at least 6 occasions. From 15% to 25% of younger school age children also may complain of recurrent abdominal pain. Abdominal pain accounts for up to 5% of visits to pediatricians' offices.

How does recurrent abdominal pain cause disease

Doctors can find a specific organic disease as a cause of the symptoms associated with recurrent abdominal pain in about 10% to 20% of children. However, the majority of children with recurrent abdominal pain have no obvious disease. That is not to say that they do not have real symptoms. Indeed, it is rare to find children who fake symptoms. Nonetheless, the lack of obvious abnormalities on testing often leads to a sense of frustration and anxiety on the part of the child, the parents, and, occasionally, the care givers.

Although it is not known the exact way that symptoms are caused in irritable bowel syndrome and functional dyspepsia-two common causes of recurrent abdominal pain-there are several current theories. The most current theory is that in both of these conditions, there is "visceral hypersensitivity." This means that the intensity of the signals from the gastrointestinal system, which travel by nerves to the brain, seems to be exaggerated. This may occur following illnesses that cause inflammation in the intestine (e.g., viral gastroenteritis), or they may occur following psychologically traumatic events that "sensitize" the brain to stimuli.

These traumatic events may be as severe as physical or sexual abuse, or they may occur in the course of family life, such as marital discord. In most cases, however, no specific cause can be found. This visceral hypersensitivity is thought to lead to symptoms when the intestine undergoes peristalsis (motility or movement) or when it is distended by gas or stool. In some patients with functional dyspepsia, it is thought that even normal amounts of acid in the upper small intestine may cause discomfort.

What are the common findings?

Irritable bowel syndrome occurs in both children and adults. The symptoms include recurrent abdominal pain-usually around the belly button or the lower abdomen-that is associated with abnormalities in stooling. Lower abdominal symptoms may include constipation, diarrhea, or a variable pattern of defecation. Commonly, the pain is relieved by defecation. Patients often complain of a sense of rectal urgency, and they may have a sense of incomplete evacuation following a bowel movement. They often complain of bloating, dizziness, and, occasionally, nausea. Weight loss, fever, or blood in the stool is unusual in irritable bowel syndrome.

In functional dyspepsia, the discomfort is centered in the upper abdomen. This discomfort may be pain-like and occasionally burn. Alternatively, some individuals only complain of a sense of nausea or early fullness after eating. Another occasional cause of recurrent functional abdominal pain is an abdominal migraine. In this condition, children develop severe abdominal pain, often in the middle of the night or early morning. Occasionally, it is accompanied by vomiting, and there may be a history of headaches. In about one-third of the cases, there is a family history of migraine headaches. Additionally, in about one-third of the cases, the child will have a history of carsickness.

How is recurrent abdominal pain diagnosed?

Recurrent abdominal pain is diagnosed based on a patient's history and a physical examination. There are no specific tests to diagnose it. It is the responsibility of the clinician and the family to use a cost-sensitive approach to this problem. However, when there are accompanying warning signs of a more serious disease, further evaluation is recommended. The warning signs include the following:

Depending upon the child's specific history and the physical findings, the physician may order screening blood work, including a complete blood count, erythrocyte sedimentation rate to look for inflammation in the body, serum chemistries, and, possibly, radiographic studies and an ultrasound. In the presence of diarrhea, a flexible sigmoidoscopy or a colonoscopy frequently is performed. In the presence of upper gastrointestinal symptoms, an upper endoscopy commonly is performed.

An additional diagnostic consideration for the symptoms is lactose intolerance. This condition is found in all ethnic groups, but it is more common in African-American, Latino, and Asian populations. It is diagnosed with a non-invasive procedure called a breath hydrogen test.

How is abdominal pain treated?

During the course of the evaluation, if a specific disease is found, then appropriate treatment is given. More often than not, the clinician will diagnose functional abdominal pain. If irritable bowel syndrome is diagnosed, reassurance is offered, and the patient and the family are informed that no serious or threatening disease exists. If there are specific triggering factors associated with the symptoms, such as school or family difficulties, then these issues need to be addressed.

If the child has diarrhea as a prominent symptom, then medications, such as dicyclomine or hyosycamine, which slow down bowel transit, occasionally are used. Low doses of medications, referred to as tricyclic antidepressants, also are used. However, these medications are not used as antidepressants; they are used to decrease the intensity of the pain signals coming from the gastrointestinal system to the brain. Dietary manipulation by increasing dietary fiber can be helpful.

Functional dyspepsia is treated with medications (e.g., ranitidine, cimetidine, omeprazole, and lansoprazole) that reduce the secretion of stomach acid. Low dose tricyclic antidepressants also may be used for severe functional dyspepsia. Patients can only be diagnosed as having functional dyspepsia after disease has been ruled out by an upper gastrointestinal endoscopy.

In cases of functional abdominal pain, where reassurance, diet, and medications do not help, a psychologist may help with biofeedback and pain control.

What are the complications?

The greatest complication of functional gastrointestinal disorders is that they are misunderstood, and the child is thought to have a serious illness. When that occurs, or when the symptoms are particularly severe, functional disability may occur. It is the responsibility of both the physician and the family to help the child to return to a normal schedule as soon as possible. While there should be no attempt to minimize the intensity of the symptoms, it also is important to not let the symptoms control the life of the child or the family.

How can abdominal pain be prevented?

Recurrent abdominal pain cannot be prevented. If the child has recurrent abdominal pain that is caused by a specific organic disease, then that disease needs to be treated. Certain diseases tend to run in families, such as peptic ulcer disease (which is caused by an infectious agent, Helicobacter pylori) and inflammatory bowel disease. Functional gastrointestinal disorders, especially irritable bowel syndrome, also may run in families; however, these disorders are so common that it is difficult to determine a particular mode of inheritance.

What research is being done?

Irritable bowel syndrome and functional dyspepsia are extremely common causes of chronic gastrointestinal symptoms in adults; therefore, the pharmaceutical industry has an aggressive research program that is focused on finding better treatments.

Dr. Hyams is the Head of Digestive Diseases and Nutrition at the Connecticut Children's Medical Center in Hartford, Connecticut, and a Professor of Pediatrics at the University of Connecticut School of Medicine.

Dr. Hyams is an accomplished clinician and investigator, and he has a special interest in functional gastrointestinal disorders in children and adolescents.